Strand drafting and tension measuring apparatus



A ril 5, 1955 F. P. STROTHER ETAL 2,705,423

STRAND DRAFTING AND TENSION MEASURING APPARATUS Filed June 11, 1952 3Sheets-Sheet 1 'FIG.].

AMPLIFIER RECORDER INVENTORS FRED P. STROTHER E 0614/? H. GRANBERIRYGEORGAE' MANN/N6 ATTORNEYS April 1955 F. P. STROTHER ETAL STRANDDRAFTING AND TENSION MEASURING APPARATUS Filed June 11, 1952 3Sheets-Sheet 2 INVENTORS FRED P. STROTHER EDGAR'H. Gl-EANBERRY GEORGEMANN/N6 ATTOR .\'E Y3 p i 1955 F. P. STROTHER ETAL 2,705,423

STRAND DRAFTING AND TENSION MEASURING APPARATUS Filed June 11, 1952 sSheets-Sheet s INVENTORS FRED P. STRUTHER EDGAR H. GPA/WHERE) GEORGEMANN/N6 *5 5 a W 1 MM ATTOR NE Y5 United States Patent STRAND DRAFTINGAND TENSION MEASURING APPARATUS Fred P. Strotller, Edgar H. Granberry,and George Manning, Shawmut, Ala., assignors to West Point ManufacturingCompany, West Point, Ga., a corporation of Alabama Application Julie 11,1952, Serial No. 292,946

7 Claims. (Cl. 73-141) This invention relates to textile testingapparatus and particularly to apparatus for measuring forces involved inthe drafting of strands of textile fibers such as sliver and roving.

It is a well known practice in the textile art to draft sliver androving, and it is of considerable interest and important to measuredrafting forces. Such information is useful in determining proper rovingtwist, and evaluating fiber finishes, and evaluating many differentfiber characteristics and their relationship to spinning and yarnqualities, for determining the effect of moisture content of thedrafting and for carrying out other basic studies in the drafting offibers.

Those skilled in the art will understand that drafting is usuallyaccomplished in apparatus having a plurality of sets of rolls betweenwhich the material to be drafted passes. Each set of rolls runs at anincreased rate of speed to stretch the strand, so to speak. In a strandof cotton fibers, for example, the individual fibers are relativelyshort and the stretching action essentially pulls the fibers over oneanother to readjust their respective positions to elongate the strand.

In the past a number of attempts have been made to measure forcesinvolved in drafting strands of textile fibers. Various methods usingconventional tensile testing machines have been designed to measure theforce necessary to start a strand of fibers to draft or be broken apart.However, since the starting force is much greater than the forcerequired to continuously draft the fibers, the results obtained are ofdoubtful value. Nevertheless, these tests are not only static tests, butare time consuming and ditficult to use. Since the forces in a draft ingzone are of dynamic nature, they should be measured continuously whilethe fibers are being drafted if the results are to be useful and to betranslated to mill practice.

Accordingly, it is a primary object of this invention to provideapparatus for the dynamic measurement of drafting forces.

Basically, the apparatus provides moving the strand past a first pointand then past a second point, the second point imparting a relativemotion to the strand in a drafting direction, with the provision thatsome motion is permitted between the first and second points, so thatincreased resistance to drafting will cause one point to move toward theother under the drafting forces. A movement detecting means is attachedto the movable part and this is employed to give an indication of therelative distance between the parts or, in other words, the draftingforces. Thus, it is a further object of this invention to provideapparatus designed along the just-mentioned lines.

A further object of the invention is to provide apparatus having a firststationary set of drafting rolls, a second set of drafting rolls to bedriven at a higher speed and movable with respect to the first, and withstrain gauge means attached to the second set of rolls for determiningthe drafting forces applied thereto.

. It is a further object of this invention to provide an air jet devicefor removing draft or roving from the rolls.

Further objects and the entire scope of the invention will becomeapparent from the following detailed descrip 2,705,423 Patented Apr. 5,1955 tion of one embodiment of the invention and from the appendedclaims.

An exemplary embodiment of the invention may be best understood byreference to the accompanying drawings, in which:

Figure 1 shows a front elevational view of apparatus according to thepresent invention and also an associated amplifier and pen recorder.

Figure 2 shows a side elevational view in section of the apparatus ofFigure 1, and

Figure 3 shows a top plan view of the apparatus shown in Figure 1.

Referring now to the drawings, which show an exemplary embodiment of theinvention, in Figure 1 the testing apparatus is designated generally as10, having connected thereto an amplifier 12 and pen recorder 14. Theapparatus 10 comprises a preferably heavy base 16 on which the remainderof the structure is mounted. The first set of drafting rolls consists ofa driven roll 18 and an idler roll 20 urged by spring 22 downwardly intoengagement with roll 18. Roll 18 is provided with a shaft 24 extendingfrom an end thereof on which is mounted gear 26, this gear meshing withgear 28 on a transverse shaft 30, which extends to the output shaft 32of a gear reduction motor unit 34. The complete assembly of rolls 18 and20, gears 26 and 28, shafts 30 and 32 and motor unit 34 may allconveniently be mounted on the base 16 by the agency of a conventionalcompound rest 36 of the type commonly found in metal working lathes. Aswill become fully apparent hereinbelow, the lathe compound rest isuseful in the practice of this invention since it provides a closesetting of the distance between the drafting rolls.

A scale 38 may be attached to the base 16 and a pointer 40 attached tothe compound rest, to accurately record the position of the rolls 18 and20 relative to the frame 16 The second set of drafting rolls consists ofdriven roll 42 and idler roll 44, the latter being urged by spring 46downwardly into engagement with roll 42.

Rolls 18 and 42 may be of metal and may be either splined or smooth. Therolls 20 and 44 are preferably covered with a suitable resilientmaterial such as rubber. Roll 18 and the body of roll 20 may be ofsteel. However, it is preferable to construct roll 42 and] the body ofroll 44 of aluminum or other light material to reduce the mass of theseparts.

Roll 42 is mounted on shaft 48 which is coupled with the output of agear reduction motor unit 50. Both the motor 50 and the rolls 42 and 44are mounted from a transverse plate member 52. The motor 50 ispreferably mounted from plate 52 on upstanding bracket 54, with theactual mounting of the motor on the plate 54 being by means of resilientwashers 56. With this type of mounting, and with a flexible connectionbetween the motor unit and the shaft 48, vibrations from the motor willnot be transmitted to the rolls 42 and 44.

The plate 52 is hung from an overhead shaft 58 by means of dependingside hanger members 60 and 62. The shaft 58 is maintained in position bytwo relatively massive supports 64 and 66 extending upwardly from thebase 16. Frictionless bearings, such as ball bearings, are provided at68 and 70 for permitting shaft 58 to be freely rotatable in the supports64 and 66.

Attached to support 66 is a strain gauge 72 of any conventional variety.Preferably, this will be a so-called unbonded strain gauge, and may beone such as described in Patent No. 2,036,458. It will be understood,however, that other types of strain gauges may be employed. Theoperating arm 74 of the strain gauge is attached to an arm 76, otherwisefixedly attached to the hanger support member 62. The strain gauge 72may be connected by leads 78 to the amplifier 12 and the output of theamplifier 12 may be over leads 80 to the pen recorder 14.

From the apparatus as thus far described, referring particularly toFigure 2, it will be understood that a sliver S may be introduced to thefirst set of drafting rolls 18, 20, which will be driven at a fairlyuniform predetermined speed by the motor unit 34. The action of spring22 will cause the sliver to be gripped between the rolls 18 and 20. Thesliver S will then be passed between the second set of drawing rolls 42and 44 and these rolls will be driven at an increased rate of speed bymotor unit 50. Accordingly, drafting of the sliver will occur along thelength of the sliver between the first and second sets of draftingrolls.

In view of the fact that the second set of drafting rolls 42 and 44 andall the associated equipment including the driving motor 50 are mountedon the pendulum structure depending from shaft 58, it will be apparentthat this structure will tend to rotate counter-clockwise as viewed inFigure 2 about the shaft 58 as increased resistance is met to thedrafting of the sliver. That is, since the rolls 42 and 44 are moved ata greater rate than rolls 18 and 20, the unit comprising rolls 42 and 44will move toward the rolls 18 and 20, or the sliver therebetween will beextended in drafting fashion.

Since the operating arm 74 of strain gauge 72 moves with the pendulumsupporting structure, the strain gauge will register any relative motionbetween the two sets of rolls. The usual unbonded strain gauge willprovide resilient restraint against motion and it, therefore,automatically set up its reading in terms of units of force and suchreading may be applied to the amplifier 12 and eventually to therecorder 14.

In operation for the testing of any particular type of textile strand,the relative speeds of motor units 34 and 50, or the combination ofgears 26 and 28, will be arranged to provide for simulated drafting aswould occur in a conventional drafting machine. The strand S is thenintroduced through the two sets of rolls and the motor units energized.By suitable calibration the pen recorder 14 may be adjusted to readdirectly in desired units of force. With the usual type of straingaugethe movement of the operating arm 74 and hence the completependulum support for the rolls 42 and 44 will move only through a veryshort range. The length of the arc at the arm 76 may be, for example,only about 0.001 inches. Thus, for all practical purposes, the positionof the rolls 42 and 44 relative to the first drawing point at rolls 18,will be fixed and the situation will correspond to that found in aconventional drafting machine. Nevertheless,

there will necessarily be some movement between the sets of runs toactuate the strain gauge and hence, in another sense, the sets of rollsare movable one to the other.

The amplifier 12 may be adjusted as will be well understood by thoseskilled in the art to provide an output for the pen recorder which willfollow every change in registered strain. However, on the other hand,integration effects may be introduced into amplifier 12 to smooth outthe resulting pen recording on the recorder 14.

The strand or sliver S on leaving the second set of rolls 42 and 44 willnormally be quite loose and considerable amounts of lint will beproduced. This lint should be removed from the vicinity of rolls 42 and44 so as to prevent a build-up of lint thereon. Such a build-up isundesirable since it adversely effects the gripping qualities of therolls on the strand and will eventually alter the diameters and hencethe peripheral speeds of the rolls. To effectively remove the strand andall lint therefrom, from the vicinity of the rolls 42 and 44, and yetprevent the introduction of spurious forces on the movable structure,there is further provided as an important aspect of this invention asuction device 80. The device 80 may be mounted from base 16 by means ofsupport 82. Air pressure may be supplied through line 84, throughpressure reduction regulator 86 and then through line 88 to a jetaperture 90 in the device 80. Aperture 90 is directed toward an opening92 in the device 80 and also opens into a conical chamber 94 having anopening at 96 in proximity to the output side of rolls 42 and 44. As airunder pressure moves rapidly through aperture 90 and out through opening92, a considerable movement of air will occur through the conicalchamber 94 as indicated by arrows 98. This will tend to draw the strandS and all lint in the vicinity through the device 80 to reappear in astream S at the side remote from rolls 42 and 44. A suitable containermay be placed to receive the material at S.

As above stated, the movement of the supporting structure for the seconddrawing rolls need be very slight to actuate the usual types of straingauges. To prevent unnecessary movement, and to also prevent damage tothe strain gauge, stops 100 and 102 may be provided to engage the plate52 at the extreme limits of the desired travel of the latter.

From the foregoing it will be understood that there is provided by thisinvention a very sensitive apparatus for measuring drafting forces.Experimental embodiments of the apparatus have been successfullyoperated and the tests thereon indicate that the device is quitesensitive and operates satisfactorily over a wide range of draftingforces.

It will be understood that the particular embodiment of the inventiondescribed in detail hereinabove, for purposes only of illustration.Since many other embodiments of the invention will occur to others uponreading this specification, it is intended that the true scope of theinvention be determined from the appended claims.

What is claimed is:

1. Apparatus of the class described comprising a base, a first set ofdrafting rolls, first motor means for rotating said first rolls, therolls and motor being supported on the base by means of an adjustmentmember, a second set of drafting rolls and motor moving means therefor,the second rolls and motor means being mounted on a pendulum framepivotally supported on uprights extending from the base, a strain gaugemounted in fixed relation to the base and having an operating arm, saidarm being attached to the pendulum support for movement therewith.

2. Apparatus of the class described comprising a first set of fixedlymounted drafting rolls, means for turning the first set of rolls at afirst substantially constant speed, a second set of drafting rollsmounted on a movable support, means movable with the support forrotating the second set of drafting rolls at a substantially constantspeed greater than the speed of the first rolls, the supporting meansand second set of drafting rolls and the moving means therefor beingmounted in pendulum manner on overhead anti-friction bearings, thearrangement being such that a strand of textile fibers or the like maybe drafted therebetween, a strain gauge connected to operate between themovable support of the second rolls and a fixed point, and meansconnected with the gauge to indicate the strain to which the gauge issubjected.

3. Apparatus of the class described comprising first means for impartingmotion at a substantially constant rate to a fiber strand to be drafted,second means for imparting motion to the strand at a substantially con-.stant rate in excess of the rate imparted by the first means,

one of said means being mounted in pendulum manner in overhead pivotmeans whereby said first and second means are movable relative to eachother, means for restraining relative motion of the first and secondmeans toward each other, and means for indicating the changes inrelative position between the first and second means, the arrangementbeing such that increased resistance to travelling moves the first andsecond means toward one another under restraint of the restrainingmeans.

4. Apparatus as defined in claim 3 wherein said indicating meansincludes a pen recorder.

5. Apparatus for measuring dynamic forces established in the drafting ofstrands of flexible textile fibers comprising a base, a first set ofdrafting rolls, means for supporting said first set of drafting rolls infixed relation on said base, a second set of drafting rolls, means forsupporting said second set of drafting rolls on said base for movementtoward and away from said first set of drafting rolls, means forrotating said sets of drafting rolls at different but substantiallyconstant rates whereby the individual textile fibers of a strand passingthrough said sets of drafting rolls will be caused to move relative toone another between said sets of drafting rolls, a strain gauge mountedin fixed relation with respect to said base and having an operating arm,said arm being connected with said second set of drafting rolls formovement therewith.

6. Apparatus as defined in claim 5 wherein said supporting means forsaid first set of drafting rolls includes an adjustment member foradjusting the fixed position of said first set of drafting rolls withrespect to said second set of drafting rolls.

7. Apparatus as defined in claim 5 wherein said supporting means forsaid second set of drafting rolls includes I anti-friction means.

References Cited in the file of this patent UNITED STATES PATENTS CooperFeb. 14, 1911 Webster Sept. 8, 1914 Hornbostel May 4, 1948 Nelson July27, 1948 Norton Sept. 1, 1953

